The Hollywood actor and sometime political activist, George Clooney, was cuffed with zip-ties and taken away in a police van after being arrested during a protest outside the Sudanese embassy in Washington DC.

Clooney, who has long campaigned against the government in Khartoum, had intended to be arrested when he planned the protest, which took place on Friday morning.

George Clooney arrested just now outside #Sudan embassy in protest against Nuba Mt killings wapo.st/x8jVZf

Joined by his father, journalist Nick Clooney, US Representative Jim Moran of Virginia and NAACP president Ben Jealous, the actor blocked the entrance to the Sudanese embassy. Clooney and the others were given three orders to disperse by the police and refused to do so.

Others taken into custody included the civil rights campaigner Martin Luther King III, and actor and comedian Dick Gregory.

"I'm just trying to raise attention," Clooney told reporters as he was led away. With his hands tied behind his back, he addressed the plight of "innocent children" in Sudan. "Stop raping them and stop starving them," he said. "That's all that we ask.

As he was led into a police van an onlooker shouted, "Thank you, George!"

"It's actually a humiliating thing to be arrested no matter what you do, but I'm glad to be standing here with my father," Clooney added.

Clooney and several others posted bail and walked free later on Friday. "You never know if you are accomplishing anything ... We hope it helps," Clooney told reporters after his release, adding that the arrest was his first and "let's hope it's my last."

The actor has been in the capital since returning from a tour of Sudan two days ago. On Wednesday he testified in front of the Senate foreign relations committee on the subject of violence in the Nuba mountains in South Kordofan, a state in Sudan near its border with newly independent South Sudan. He told the senators: "We found children filled with shrapnel, including a nine-year-old boy who had both of his hands blown off."

Clooney accused Sudanese president Omar al-Bashir, government official Ahmad Harun and defence minister Abdelrahim Mohamed Hussein, of orchestrating systematic killing in the area.

Clooney has called on US officials to pressure the Chinese government to force the government of Sudan to open the southern region of the country to relief efforts. As the rainy season approaches, large numbers of the region's inhabitants could face starvation.

On Wednesday, Clooney met President Barack Obama to express his concerns for the people of Sudan. Clooney said he left the meeting optimistic that Obama would pressure Chinese president Hu Jintao to seek a resolution to the region's ongoing conflict at an upcoming meeting.

He appeared on NBC's Today show earlier this week to explain his stance.

Earlier this month the International Criminal Court issued an arrest warrant for Hussein listing 41 counts of crimes against humanity and war crimes allegedly committed in Sudan's Darfur region. Al-Bashir and Harun are also facing charges of war crimes allegedly committed in Darfur.

Clooney described the men as "the greatest war criminals of this century by far". He has called on US officials to pressure the Chinese government to push the government of Sudan to open the southern region of the country to relief efforts. As the rainy season approaches, large numbers of the region's inhabitants could face starvation. USAID has estimated that as many as 250,000 people in South Kordofan could face a serious emergency by the end of April if violence and a lack of humanitarian access in the region persists.

Inevitably, his arrest on Friday prompted a wide range of socal media reaction: